B. the temperature of a liquid after it is heated for 10 seconds
Answer:
x= (2/5)-(2y/5) (Im not sure if this is what you need but this is the answer simplified)
Step-by-step explanation:
Move all terms that don't contain x to the right side and solve.

At first Divide the figure into two rectangles, I and Il
Area of figure l is ~
Area of figure ll is ~
Area of whole figure = Area ( l + ll )
that is equal to ~
F(x)=-4x-1 if you sub 3 into it you get 3(-4)-1 which is -13 and 2x+4=10